The present invention relates to a radio frequency IC chip which is supplied with power using radio waves for communications and in which information can be read and written using the radio waves in a non-contact manner.
In recent years, attention has been focused on a technology called radio-frequency identification (RF-ID) in which a person or an object is identified and managed using a radio frequency integrated circuit (RFIC) chip. An RFIC chip (also referred to as an RF-ID tag, an RFIC tag, and the like) used in RF-ID communicates with a reader/writer by use of radio waves or electromagnetic waves, and can operate without having a battery by a technology for transmitting power from an antenna side in a non-contact manner (e.g., see Patent Documents 1 and 2 and Non-Patent Document 1).
Generally, an RFIC chip has a non-volatile memory in the chip, and data can be read from or written into the non-volatile memory by communicating with the chip by radio waves or the like using a reader/writer. By using the non-volatile memory, written data does not disappear but is maintained even when power supply is cut off because the RFIC chip stops receiving radio waves from the reader/writer.
Utilizing this, distribution management and process management for items can be performed by attaching the RFIC chip to an item in a distributing stage or a manufacturing stage, and appropriately reading information from, or writing information into, the non-volatile memory in each stage.
(Patent Document 1) Japanese Unexamined Patent Publication No. 2001-291079
(Patent Document 2) Japanese Unexamined Patent Publication No. 2003-331238
(Non-Patent Document 1) “Kiso kara wakaru musen IC tag” (online), Jan. 20, 2004, Nikkei Business Publications, Inc., (searched on Jul. 30, 2004), the URL <http://itpro.nikkeibp.co.jp/free/NBY/RFID/20031204/3/mokuji .jsp>
However, as described previously, data written in a non-volatile memory is maintained even when power supply is cut off because an RFIC chip stops receiving radio waves from a reader/writer. Accordingly, deleting already-written data requires an effort because other data needs to be overwritten using the reader/writer. Further, convenience is insufficient because data cannot be deleted in the state where radio waves from the reader/writer are not received.
Moreover, data written in the non-volatile memory can be read using the reader/writer anytime. Therefore, from the viewpoint of information security, it has been difficult to use the RFIC chip in such a manner that information to be concealed is written into the non-volatile memory.